Tuning the work function of indium-tin-oxide electrodes for low-temperature-processed, titanium-oxide-free perovskite solar cells

Abstract

In this work, low-temperature-processed, titanium-oxide-free perovskite solar cells (PSCs) with power conversion efficiency (12.2%) comparable to that of titanium-oxide-based PSCs were fabricated. The fabricated PSCs exhibited a small hysteresis owing to the two-step preparation method employed for perovskite films. A poly [(9,9-bis(3'-(N, N-dimethylamino) propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)] (PFN)tuned indium-tin-oxide (ITO) electrode was employed as a cathode and phenyl-C61-butyric acid methyl ester (PCBM) was used as an electron transport layer. Owing to the formation of surface dipoles, the work function of the ITO electrode could be tuned from -4.75 eV to -4.12 eV, which is more efficient for electron collection. Our proposed method significantly lowers the PSC processing temperature from 500 degrees C to 100 degrees C, which is advantageous for commercialization of PSCs and fabrication of flexible PSCs. (C) 2017 Elsevier B. V. All rights reserved.